MCU-based DMA function control AD converter peak value sampling method

Abstract

The invention relates to an MCU-based DMA function control AD converter peak value sampling method. The method comprises the following steps of configuring a timer DMA function of an MCU according toa time sequence requirement of an AD converter; configuring a port register connected with the AD converter to point to the first buffer area, transmitting AD converter data to the first buffer area through a port of the MCU, and entering an interrupt execution program; in the first stage of interrupting the execution program, closing the DMA within the time less than 1us, reappointing the data port register to transmit to the second buffer area, and then restarting the DMA; in the second stage, using a program to find the maximum value and the minimum value in the AD voltage and current datafilled in the previous buffer area, and calculating an average value; and in the third stage, using the MCU to execute other programs. According to the invention, the loss-free continuous full sampling of a voltage and a current can be realized by using the simplest circuit diagram, and the measurement of voltage and current peak values and ripples can be realized.

Description

Technical field: [0001] The invention relates to the fields of instrumentation and electronic measurement, in particular to a method for sampling the peak value of an AD converter based on the DMA function of an MCU. Background technique: [0002] In the field of electronic measurement, to realize the peak value and ripple measurement of voltage or current, usually use the hardware peak sample and hold circuit or FPGA / CPLD to connect AD analog-to-digital converter for sampling and then pass the method to MCU through FPGA / CPLD, such as figure 1 , figure 2 shown. These methods have their own shortcomings, and it is difficult to achieve peak and ripple measurements without loss of peak sampling and in arbitrarily controllable time periods. Moreover, the method of adding CPLD or FPGA increases the complexity of the circuit and increases the cost. Invention content: [0003] The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a...

AI Technical Summary

Problems solved by technology

These methods have their own shortcomings, and it is difficult to achieve no loss of peak sampling and peak and ripple measurements in arbitrarily controllable time periods.

Moreover, the method of adding CPLD or FPGA increases the complexity of the circuit and increases the cost.

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